Control system for looms

ABSTRACT

Solid-state logic circuitry of the computer type for accepting start or stop signals from numerous sources in a fly-shuttle loom and for translating those signals after suitable time-delay into command signals for an electrical clutch-brake loom motor. Improved shuttle sensing means is provided for signalling the shuttle boxing condition during each picking cycle.

United States Patent r 13,570,550

References Cited UNITED STATES PATENTS 2,753,894 7/1956 Lovshin et al.

[72] Inventor Walter James Budzyna East Douglas, Mass. [21 Appl. No. 768,428

mfl u a AP 91 66 99 11 44 66 9 q w 91 300 4 9 32 [22] Filed Oct. 17, 1968 [45] Patented Mar. 16, 1971 [7 3] Assignee North American Rockwell Corpqration Pittsburgh, Pa.

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Patented Mmh 16, 1971 5 Sheets-Sheet 1.

ATTORNEY Patented March 16, 1911 3,570,550

5 Sheets-Sheet 2 INVENTOR WALTER 8mm Buuzmn To CLUTCH SDLENOID ATTORNEY Patented March 16, 1971 5 Sheets-Sheet 5 A N Y R1 00 Tu m8 V. NM n a R E m Y B fiM QMM ATTORNEY Patented March 16, 1971 3,570,550

5 Sheets-Sheet 4 V INVENTOR WALTER. James Bu 07mm l k v IIIIIIIIN \u ATTORNEY Patented March 16, 1971 5 Sheets-Sheet 5 THERMAL OVERLOAD M LOOM MOTOR SWITCH w POWER MAINS INVENTOR WALTER James Buozma ATTORNEY CONTROL SYSTEM FOR LOOMS BACKGROUND OF THE INVENTION This invention pertains to electronic control systems for flyshuttle looms of the type adapted to be driven by clutch-brake loom motors. More particularly the invention pertains to control systems for such looms whereby loom stoppage may be effected through signals initiated by detecting any one of the common weaving faults, or by power failure at the loom, or manually by operating switches. The invention further relates to sensing means for shuttle protection whereby the absence of the shuttle in a shuttle box at a preselected instant of each cycle will signal through the logic system for a loom stop.

In loom control systems the most severe requirements for the stopping mechanism is that of shuttle protection in the event of abnormal shuttle flight. It is essential that the shuttle be within a shuttle box prior to the beat-up of each filling pick to avoid damage to either or any combination of the shuttle, reed, or a plurality of warp threads. As loom speeds have been continually increased, the available time for effecting loom stoppage for cause has diminished to a point where prior art systems may not e considered entirely satisfactory. Means for transmitting a loom-stop signal when a delayed shuttle has been detected, have not been completely dependable nor sufficiently rapid to function within the allowable time. Shuttle sensing members have been tried in positions inwardly-of the warp shed in attempting to increase thetime element. However, this has added the further possibility that a shuttle delay might still occur after it had passed the sensing members. It is considered desirable that the sensing action be performed as late in the cycle as is possible to assure full protection. This invention is directed toward solution of these problems with a control system for signalling and initiating loom stoppage within the time available.

SUMMARY OF THE INVENTION This invention includes a solid-state computer-type logic system for accepting start and stop commands for a fly-shuttle loom and for translating those commands with predetermined timing to start or stop command signals for an electrically operated clutch-brake loom motor. The system provides pushbutton starting and stopping, filling break stopping, shuttle protection stopping, power failure stopping, and brake release during loom stoppage. The system includes means to avoid a stop signal during insertion of the first pick following a filling break stop when ordinarily the empty shed would signal for stoppage before the shuttle could insert the first pick. Additional means provides a cloth takeup disconnect action automatically upon signal for normal brake release during loom stoppage. These functions are initiated by either switch closures such as pushbuttons for starting and stopping or by magnetically induced pulses for indicating correct shuttle boxing for shuttle protection. The signals are processed by logic flipflops and logic NAND or NOR gates to provide the signals needed by the clutch-brake solenoid control unit to properly energize either the ciutch or the brake solenoids. Proper timing of the stop signals relative to each picking cycle to stop the loom at the desired position is provided by magnetic pickup coils selectively mounted angularly around the crankshaft.

The logic system is built with Digital Equipment Corporations K-Series Logic Modules, these modules being interconnected to obtain the proper logic functions, however any type logic may be used.

It is a general object of the invention to devise a start/stop control system for a fly-shuttle loom which, through computerlike logic circuitry will transmit signals nearly instantaneously to the clutch-brake drive.

It is a further object of the invention to devise a control system for a loom which shall combine the speed and dependability under adverse conditions of solid-state digital circuitry with a rapidly responding clutch-brake motor drive.

It is a further object of this invention to devise novel sensing means for shuttle protection whereby a pickup coil near each shuttle box will induce a pulse when the shuttle is present and allow the loom to continue, but when the shuttle is absent or late in arriving, no pulse or a late pulse will be induced and the loom will be stopped.

It is a further object to devise a control system for translating timed loom-stop commands from signals initiated by warp and filling sensing devices.

It is a further object of the invention to devise a control system which shall include the so called first pick protection" whereby a stop signal initiated before the initial picking of the shuttle at a signalled loom start will not cause loom stoppage, but any stop signal subsequent to this initial picking will properly stop the loom.

It is a still further object to include circuitry in the control system to assure safety-against unexpected startup and further to provide a timed start-up delay following a rapid start-stop sequence to permit the starting capacitors to become fully charged.

It is another object of the invention to provide means for causing brake release and takeup pawl release during loom stoppage to permit manual movement of certain loom mechanisms.

It is also an object of the invention to provide circuitry whereby loom stop signals from a variety of sources and numerous timing pulses are all directed through a single logic gate for effecting command signals to the clutch-brake motor.

These and other objects of the invention will become apparent as further details are disclosed.

BRIEF BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described by reference to a specific embodiment thereof as illustrated in the accompanying figures of drawing, wherein:

FIGS. 1 and 2 combined, show the circuitry of the logic system diagrammatically, the two figures being interconnected through wiring numbered 20 to 23;

FIG. 3 is a rear view in perspective of the right hand shuttle box;

FIG. 4 is'an enlarged view of a portion of FIG. 3 with different perspective;

FIG. 5 is a rear view in perspective of the handwheel end of the loom crankshaft having the timing coils of the invention supported thereon;

FIG. 6 is a plan view of the opened timing coil casing of FIG. 5 away from the loom;

FIG. 7 is a perspective view of the takeup release linkage attached to the loom; and

FIG. 8 is a circuit diagram for the takeup release mechanism of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to FIGS. 1 and 2, which show the computertype logic system diagrammatically with the wiring of the two figures being interconnected at points 20, 2!, 22, and 23. The

logic system is built with modules which are interconnected A control flip-flop 25 is the heart of the control system withall start and stop command pulses being applied to this flipflop, start command pulses from logic gate 26 (FIG. 2) and stop command pulses from logic gate 27 (FIG. 1). The output of flip-flop 25 is connected to logic gate 28 which drives the clutch-brake control unit (Shown in FIG. 8). A logic 1 signal is required by the control unit to energize the motor clutch solenoid and a logic 0 signal is required to energize the motor brake solenoid.

LOOM START SEQUENCE To start the loom, line power is applied to the clutch-brake control unit. A stepdown transformer (not shown) in the unit provides 12.6 volts AC, center tapped, from the line voltage, which is applied to power supply module 29. The outputs of power supply module 29 are the 5 volts DC used by the logic system and a pulse (during power turn-on only) which is applied to control flip-flop 25 through a gate expander 30. The 0 pulse is used to initialize the state of flip-flop 25 to the Loom Stopped condition and ensures that the output of logic gate 28 will be 0 and the motor brake solenoid energized.

A start sequence begins when either pushbutton 31 or 32 is depressed. Capacitor 33 will discharge through the pushbutton contacts providing sufficient current flow to break down any oxide filmwhich may have formed on the switch contact surfaces. Resistor 34 connected from 24 volts DC to the pushbuttons 31 or 32 provides approximately 0.1 ampere for the same purpose. The 0 generated by the switch closure is applied through a noise-suppression network including resistor 35, capacitor 36 and isolation diode 37 to inverter 38. Resistor 39 connected to the input of inverter 38 ensures that a logic 1 is applied to the input when the pushbuttons 31 and 32 are open. Inverter 38 inverts the 0 and applies a 1 to inverter 40 and one input of logic gate 26. The output of inverter 40 is normally 1 changing to 0, milliseconds after the 1 is applied to the input, the delay being caused by capacitor 41.

The output of logic gate 26 will be 0 only when all its inputs are 1. With the loom stopped and all conditions stabilized, all inputs except the input connected to inverter 38 will be 1. When the inverter 38 output changes to 1 during a start pulse the output of logic gate 26 will go to 0. Five milliseconds later the logic gate 26 input connected to inverter 40 changes to 0 causing the logic gate 26 output to change back from 0 to 1. In this manner a 5 millisecond 0 level pulse is formed from a Start pushbutton 31 or 32 command. This pulse is applied to control flip-flop 25 changing its state to the Loom Running condition.

SAFETY CIRCUITS In order to provide a positive safe condition during which time the loom cannot possibly be started, two methods are used. In the first method, the power line 42 to the clutch solenoid is routed through two safety selector switches 43 and 44, connected in series. Both of these switches must be closed be fore the clutch solenoid can be energized. Opening either one will place the loom in a safe condition.

In the second method, switches 45 and 46, wired in series, are connected through the contact-forming capacitor 47 and resistor 48 and through the noise-suppression network including resistor 49, capacitor 50 and isolation diode 51 to an inverter 52. A resistor 53 is connected to the input of inverter 52 to insure that a logic 1 is applied when the switches are open. The output of inverter 52 will be 0 if either of the two switches 45 or 46 is opened. This 0 is applied to one input of warp stop memory flip-flop 54 and also to one input of gate expander 55 for logic gate 26. The 0 input to flip-flop 54 will cause the loom to stop just as though a warp break or a pushbutton stop had occurred. This prevents the loom from running more than one pick after the safety switch is opened and stops the loom in the normal stop position should the safety be accidentally applied while the loom is running. The 0 input to gate expander 55 prevents the output of logic gate 26 from becoming 0 should the start pushbutton 31 or 32 be pushed, thereby disabling the starting circuit as a safety measure. When the switches 45 and 46 are closed, the output of inverter 52 will return to 1, removing the stop signal from flip-flop 54 and the start-disable signal from gate expander 55.

PROTECTION STOP In FIGS. 3 and 4 a portion of the right-hand end of a loom is shown with a shuttle box generally designated 56. It will be understood that a second shuttle box is in position at the other end of the loom and the inventive mechanism to be now explained is duplicated in that left-hand box. (Not shown) The shuttle box '56 is supported at the end of a lay 57 over which a shuttle 58 is propelled in repeating weaving cycles for inserting picks of filling into opened sheds of warp yarns (not shown). The rearward wall of the shuttle box 56 is a pivotally supported and inwardly biased binder 59, pivoted at point 60, for impeding the shuttle in ending its flight. The binder 59 will be pivoted outwardly by the shuttle as it enters the shuttle box 56 and inwardly as it leaves. Binder pickup coils 61 and 62 (FIG. 1) are secured to the lay 57 with one being beneath each binder 59 near the point of its greatest pivotal movement. (FIGS. 3 and 4) Fastened to each binder 59 upon its outer surface and in alignment with a pickup coil 61 or 62 is a pole piece 63 formed of steel and having a flat under surface which is movable above and away from the pickup coil 61. The pickup coils 61 and 62 are used to sense the motion of the binders 59 as the shuttle 58 traverses the loom. When the shuttle is picked from a shuttle box, the binder will pivot slightly as it comes to the rest or empty-box position. By this movement the pole piece 63 will induce a pulse in the coil 61. When the shuttle contacts the binder on the opposite side of the loom, that binder will be forced away from the rest position and its pole piece 63 will induce a pulse in'the pickup coil 62.

When a pulse is induced in a pickup coil 61 or 62, it forward-biases the transistor 64 or 65 connected to it, causing the transistor to conduct. This applies a 0 to the input of Protection Memory flip-flop 66 changing its output connected to logic gate 27 from 1 to 0.

Referring now to FIGS. 5 and 6 together with FIG. 1, a handwheel 66' is fastened for rotation upon the loom crankshaft 67 which is arranged to complete one rotation per pick or per weaving cycle. A cylindrical casing 68 is supported by having the crankshaft joumaled therethrough and is secured against rotation by a radially extending tab 69 restrained in a fixed bracket 70 on the loom. (FIG. 5) A cover 71 which encloses the casing 68 may be fastened as by screws 72. A bearing sleeve 73 of the casing 68 is fastened to the crankshaft 67 by a setscrew 74 and carries with it for rotation a magnet 75 outwardly directed. (FIG. 6) Spaced about the inner peripheral wall of the casing 68 are five coils 75', 76, 77, 78 and 79 each fastened adjacent to the circular path of the magnet 75 as it rotates and each being angularly adjustable relative to the casing 68 by means of circumferential slots 80. (FIG. 5) Each of the five coils is wired into the logic circuitry as in FIG. 1.

Protection coil 76 will be pulsed by the crankshaft mounted magnet 75 slightly after the moment the shuttle should have arrived at the receiving shuttle box. This moment in a weaving cycle may be preset selectively by adjusting the angular or circumferential position of the coil 76. The pulse from coil 76 is applied to transistor 81, which in turn switches the input of inverter 82 to 0 for 10 milliseconds. The output of inverter 82 will be a 10 millisecond-long 1 pulse.

The output of logic gate 27 will be 0 thereby applying a stop command to the control flip-flop 25 when both inputs are at the I level. This can occur only when shuttle coils 61 and 62 fail to set the output of flip-flop 66 to 0. If the input of logic gate 27 connected to flip-flop 66 is 1, which means the shuttle coils 61 and 62 have not been pulsed, and the input connected to inverter 82 is also 1, as will occur every revolution of thecrankshaft 67, then the output of logic gate 27 connected to flip-flop 25 will go to 0 for 10 milliseconds. This pulse will cause flip-flop 25 to change its state from the Run condition to the Stop condition, thereby sending a Stop command through logic gate 28 to the clutch-brake control unit. The final stopped position of the loom depends upon the instant during the weaving cycle that the synchronizing pulse occurs and can be adjusted by changing the position of the coil 76 as explained above.

In the weaving-cycle sequence from picking to boxing of the shuttle, the input of flip-flop 66 will be pulsed twice, once by the binder coil on the picking side of the loom and once by the coil on the boxing side, coils 61 and 62. The pulse from the picking side, occurring first, will cause the output of flip-flop 66 to go to ll, indicating proper boxing. This is an undesirable transmitted to the reset input of flip-flop 66 thus resetting the 5 output of flip-flop 66 to a l. Flip-flop 66 will remain at 1 until the shuttle in entering the receiving shuttle box will trigger either coil 61 or 62 and set flip-flop 66 to 0 and allow flip-flop 2.: to remain in the Run condition.

FILLING STOP A center fork switch 84 is mechanically connected to the filling stop motion (not shown) of the loom and will close upon detection of a filling break by the stop motion. Switch 84 is connected through the contact forming capacitor 85 and resistor 86 and through the noise-suppression network including resistor 87, capacitor 88, and isolation diode 89 to the flip-flop 90. A resistor 91 is connected to the input of flip-flop 90 to ensure that a logic 1 is applied when the switch 84 is open. The output of flip-flop 90 will be set to 1 when switch 84 closes. This allows rapid detection and retention of a signal from the switch 84, should vibration of the loom cause the filling break detector switch to bounce intermittently after closing.

At a predetermined instant in the weaving cycle, the coil 77 and its transistor 92 will be pulsed by the magnet 75 as the crankshaft 67 rotates. A millisecond long 0 pulse will be applied to inverter 93 which applies a 1 pulse to one input of gate expander 94.

Gate expanders 94 and 95 are connected to logic gate 27 to OR expand its NAND function. If both inputs of logic gate 27 or gate expander 94 or gate expander 95 are l, the output of logic gate 27 will be 0. When the input of gate expander 94 connected to flip-flop 90 is 1 by reason of a filling break detector switch 84 closure and the other input becomes 1, as will occur every revolution of the crankshaft 67, the output of logic gate 27 will drop to ii for 10 milliseconds. This will trigger flip-flop 25 to the Loom Stopped condition and a stop signal will go to the clutch-brake control unit.

Flip-flop 90 will be reset by coil 75 to prevent a false loom stop should the filling break detector switch 34 be Closed when the loom is started. However, any closure of that switch which may occur after flip-flop 96 has been reset will cause a loom stop.

WARP STOP AND MANUAL STOP The circuit for signalling a warp yarn break or for a manual stop is similar to the filling stop circuit. A switch closure from either the warp stop motion switch 96, a manual stop pushbutton 97 or 98, or a single-pick switch 99 or 100, will apply a 0 through the contact forming capacitor 101 and resistor 102 and through the noise suppression network including resistor W3, capacitor 194, and isolation diode 105 to the flip-flop 54. A resistor 106 is connected to the input of flip-flop 54 to ensure that a logic I is applied when the switches are open. The output of flip-flop 54 will be a i. applied to one input of gate expander 95. At the proper point in the weaving cycle for a warp break stop, the timing coil 79 will be pulsed by the magnet 75 and through transistor E07 and inverter 108 will apply a 10 millisecond pulse to the other input of gate expander 95. This will cause a 0 output at logic gate 27 thus setting flip-flop 25 to the Loom Stopped condition to stop the loom.

Flip-flop 54 will be reset when the loom is started by the start pulse from logic gate 26. One input of fiip-flop 54 is also connected to inverter 52 to stop the loom when the safety switches 43 or 44 are opened.

FIRST PICK PROTECTION If, following a stoppage signal, the loom were turned backward manually to the back-center position of the crankshaft and then restarted, one of the following loom stops might occur before the shuttle could be picked:

a. a protection stop since no pulses would have been received from the pickup coils 61 or 62 to cancel a protection stop signal;

b. a warp stop since a stop signal 1 from flip-flop 56 could be present at gate expander and would stop the loom at the first pulse fromthe warp stop timing coil 79; or

c a filling break stop as the pick of filling might not be in position to support the filling fork and a filling break stop would result.

To prevent these false stops from occurring when the loom is restarted, a first pick protection circuit cancels all stop signals from logic gate 27 until the shuttle has been picked from the shuttle box and is in flight across the loom. Gate expanders 109, 110, and Ill are connected to AND expand the input of logic gate 27, gate expander 94, and gate expander 95, respectively. All three gate expanders 109, H0 and 111 are connected to the output of flip-flop 112.

When the loom is started, the pulse from logic gate 26 is applied to one input of flip-flop 112, setting its output from I to t). This 0 is applied to the three gate expanders I09, 110 and 111 and will prevent the output of logic gate 27 from becoming 0 should its two inputs or those of gate expanders 94 or 95 become 1 by reason of a stop command. First pick protection reset coil 78 will be pulsed by the magnet 75 while the shuttle is in flight and this pulse, when applied through transistor 113 to flip-flop 112, will reset the output of flip-flop 112 to 1, allowing logic gate 27, and gate expanders 94 and 95 to function normally. The output of flip-flop 112 will remain 1 until the loom is stopped and restarted again.

Once the loom has started, the 0 output of flip-flop 25 is appliedto timer H4 whoseoutput will change from 1 to 0, 50 milliseconds after the 0 is applied to the input. Timer 114 is connected to the start circuit through gate expander 55 and when its output is 0 will prevent any subsequent start signals from passing through logic gate 26. This is done to prevent a start signal, accidentally applied while the loom is running, from activating the first pick protection circuit which would prevent a necessary stop from occurring until the following pick. When the loom is stopped the output of timer 114 will change to l as soon as the flip-flop 25'output changes to l and will allow a start signal to pass through logic gate 26.

BRAKE RELEASE To permit manipulation of the loom while stopped, a circuit for brake release is included and a sequence is initiated by the Safety-Release switches 45 and 46. Wheneither switch is moved from the Run position, a l is applied to inverter 52 which in turn applies a 0 to flip-flop 54 and gate expander 55 which stops the loom if it is running and prevents any start signal from triggering flip-flop 25. When either switch 45 or 46 (FIG. 2) is moved further to the Release position M5 or 116 an 0 is applied through the contact forming capacitor 117 and resistor 118 and through the noise-suppression network including resistor ll9,'capacitor 120, and isolation diode 121 to inverter 122 which applies a l to one input of logic gate 1.23. A resistor 124 is connected to the input of inverter 122 to insure that a logic 1 is applied when neither switch is in the release position or 116. The other input to logic gate 123 is connected to the output of flip-flop 25 and will be I only when the loom is stopped. When both inputs of logic gate I23 are 1 its output, connected to brake release delay timer 125, will be 0. The output of timer 125 will change from 1 to 0 three-fourths of a second after the input changes. This 0 is applied to logic gate 28, changing its output to l or the loom Running condition. The three-fourths of a second time delay is necessary to prevent the brake from being immediately released should the Release switch be closed while the loom is running.

With the output of logic gate 28 now at 1 the loom would be running except for one condition. Once switch 45 or 46 is moved from the Run position into the Release position H5 or 116, the power lines 42 from-the clutch-brake control unit to the clutch solenoid will be opened by switch 43 or 44 preventing the clutch solenoid from being energized. In effect a Run signal has been applied to the control unit which through switching circuitry will deenergize the brake solenoid and release the brake. When a safety-release switch is moved from its release position the outputfrom inverter 122 will change to 0, the output of logic gate 123 and timer 125 will rise to 1 and the output of logic gate 28 will change back to to thereby reapply the brake.

TAKEUP RELEASE It is desirable to disconnect the takeup mechanism during manual operation of the loom to prevent thin or void places in the cloth. This can be done automatically at the time of brake release by the use of an antitakeup solenoid 126 (FIGS. 7 and 8) to release the holdback pawl 127 of the takeup mechanism to prevent the ratchet wheel 128 from advancing as the loom is rotated by hand. A fixed link 129 connects the solenoid 126 to a lever'130 pivotally fixed to a shaft 131 which carries the pawl 127. The solenoid is wired as shown in FIG. 8 and during normal loom operation switches 43 and 44 are in the Run position whereby the clutch solenoid is connected to the clutch-brake control unit. When the loom is stopped, and either safety selector switch 43 or 44, moved from the Run to the Release position, the clutch solenoid will be disconnected and the solenoid 126 connected to the control unit. Threefourths of a second after switch 43 or 44 is moved to the Release position the control unit is changed to the Loom Running condition by the logic system as explained under Brake Release above. The brake solenoid will be released by the control unit and the antitakeup solenoid 126 energized. This allows the loom to be turned manually without having the takeup mechanism engaged. When the switch 43 or 44 is moved away from the Release position, solenoid 126 will be disconnected from the control unit and the pawl 127 will be reengaged.

START DELAY TIMER To assure sufficient time for the large capacitors associated with the clutch-brake motor control unit to become fully charged following rapid start-stop sequences, a start delay timer is included in the circuitry of this invention. The start delay is initiated when flip-flop 25 changes state from the Run condition to the Stop condition. The 1 output of flip-flop 25 is applied to logic gate 132 which is connected to start delay timer 133 and will apply a 0 to timer 133 when both its inputs are 1. One input of logic gate 132 is connected to timer 125 to obtain the start delay function when the brake is reapplied after brake-release sequence. The output of timer 133 will be 1 and change to 0, 4 seconds after both inputs of logic gate 132 go to l.

The inputs of logic gate 134 are connected to control flipflop 25 and timer 133. The input from flip-flop 25 will change to 1 when flip-flop 25 goes to the Stop condition; the input from timer 133 will normally be at 1 and change to 0, 4 seconds after the loom stop. When both inputs are at 1, a 0 from the output of logic gate 134 is applied to gate expander 55 which prevents any start signal from passing through logic gate 26.

This nonstart condition will exist for 4 seconds until the output of timer 133 changes from 1 to 0. When the change occurs, the output of logic gate 134 will change back to 1 and allow a start signal from inverters 38 and 40 to pass through logic gate 26 to flip-flop 25.

POWER FAILURE PROTECTION In the event of power failure or a thermal overload shutdown of the loom motor, it is necessary that an intentional loom stop be effected rather than allowing a gradual slow down of the mechanism. The stop should be at the manual or warp-break stop position to facilitate restarting when power has been reestablished. A power failure detection circuit (FIG. 2) is included in which an auxiliary winding on the motor stator (not shown) provides 15 volts AC to a diode 135 which rectiiies the AC voltage to be filtered by a resistor 136 and a capacitor 137. The base of a transistor 138 is connected to capacitor 137 through a current limiting resistor 139. The collector of transistor 138 is connected to the 5-volt logic supply through resistor 140 and also to the base of a transistor 141. The collector of transistor 141 is connected to the 5-volt logic supply through resistor 142 and also to one input of gate expander 143. (FIG. I)

With 15 volts AC applied to diode 135, transistor 138 will be forward biased by the voltage stored by capacitor 137. The collector of transistor 138 will be essentially at ground potential, causing transistor 141 to be biased OFF. Since transistor 141 is not conducting, its collector will be at the 5 volt potential applying a 1 to gate expander 143. When the 15 volt potential is removed from diode 135 because of either a power failure or the motor's thermal overload protection, capacitor 137 will be discharged by resistor 144 and the forward bias will be removed from transistor 138. Transistor 138 will turn off thus applying 5 volts through resistor 140 to the base of transistor 141 which will then be forward biased. It's collector will go to ground potential, applying a 0 to gate expander 143. The l) at gate expander 143 will cause flip-flop 54 to change state just as though a stop pushbutton 97 or 98 has been pressed, and the loom will stop at the normal position as timed by coil 79. To ensure that the 5 volts from the power supply module 29 does not decay too rapidly following the power failure, capacitor 145 stores sufficient energy for the logic to function for approximately 1 second after the decay of the input power.

Iclaim:

1. In a loom having a lay, a shuttle for reciprocal movement along said lay in repetitious weaving cycles during each of which the shuttle is transferred from one end of the lay to the other end thereof, a shuttle box formed upon each end of said lay for receiving said shuttle at the ends of the weaving cycles, each said shuttle box having a pivotable member biased inwardly of said box for decelerating the shuttle as it enters the box, a clutch-brake motor anda control therefor for starting, driving and stopping the loom, shuttle protection means for stopping the loom at the end of the weaving cycle if the shuttle is not-properly received in said shuttle box toward which it is traveling during such cycle, said shuttle protection means comprising a pulse inducing element associated with each said shuttle box, each said pulse inducing element being connectedto be actuated by the movement of said pivotable member upon entry of a shuttle into the associated shuttle box and operative when actuated to generate a signal indicative of the entry of said shuttle into said associated one of said shuttle boxes, means operative for a limited period of time toward the end of each weaving cycle for generating a loom stop signal which, if transmitted to said clutch brake motor control, would stop the loom, and means normally operative during each weaving cycle and operative only in response to a signal from the pulse inducing element associated with the shuttle box toward which the shuttle is traveling during any such weaving cycle to prevent transmission of such stop signal to said control whereby loom operation will continue when the shuttle is properly boxed in the receiving shuttle box at the end of the weaving cycle but will terminate otherwise.

2. The device according to claim 1 wherein said pulse inducing elements are inherently operative to generate a first signal from the picking side of the loom and a second signal from the receiving side during each weaving cycle, and wherein means are provided for presenting said stop signal transmission prevention means from responding to said first signal.

3. The device according to claim 1 wherein each of said pulse inducing elements comprises a pickup coil positioned to place its magnetic field in alignment with the path of movement of said pivotable member, and a pole piece member secured upon and movable with each said pivotable member out of and into the magnetic field of its said pickup coil.

a coil disposed adjacent the iiafh of movement of said magnet and in which a pulse is induced duri ment ofsaid magnet.

ng each cycle of move- 

1. In a loom having a lay, a shuttle for reciprocal movement along said lay in repetitious weaving cycles during each of which the shuttle is transferred from one end of the lay to the other end thereof, a shuttle box formed upon each end of said lay for receiving said shuttle at the ends of the weaving cycles, each said shuttle box having a pivotable member biased inwardly of said box for decelerating the shuttle as it enters the box, a clutch-brake motor and a control therefor for starting, driving and stopping the loom, shuttle protection means for stopping the loom at the end of the weaving cycle if the shuttle is not properly received in said shuttle box toward which it is traveling duriNg such cycle, said shuttle protection means comprising a pulse inducing element associated with each said shuttle box, each said pulse inducing element being connected to be actuated by the movement of said pivotable member upon entry of a shuttle into the associated shuttle box and operative when actuated to generate a signal indicative of the entry of said shuttle into said associated one of said shuttle boxes, means operative for a limited period of time toward the end of each weaving cycle for generating a loom stop signal which, if transmitted to said clutch brake motor control, would stop the loom, and means normally operative during each weaving cycle and operative only in response to a signal from the pulse inducing element associated with the shuttle box toward which the shuttle is traveling during any such weaving cycle to prevent transmission of such stop signal to said control whereby loom operation will continue when the shuttle is properly boxed in the receiving shuttle box at the end of the weaving cycle but will terminate otherwise.
 2. The device according to claim 1 wherein said pulse inducing elements are inherently operative to generate a first signal from the picking side of the loom and a second signal from the receiving side during each weaving cycle, and wherein means are provided for presenting said stop signal transmission prevention means from responding to said first signal.
 3. The device according to claim 1 wherein each of said pulse inducing elements comprises a pickup coil positioned to place its magnetic field in alignment with the path of movement of said pivotable member, and a pole piece member secured upon and movable with each said pivotable member out of and into the magnetic field of its said pickup coil.
 4. The device according to claim 1 wherein said stop signal generating means includes a magnet mounted within the loom for cyclic rotation in accordance with the weaving cycles and a coil disposed adjacent the path of movement of said magnet and in which a pulse is induced during each cycle of movement of said magnet. 